markeringgjenfangst

Markeringgjenfangst, a Norwegian term, translates to "capture-recapture" in English. It is a scientific method used to estimate the size of a population. The technique involves capturing a sample of individuals from a population, marking them in a way that doesn't harm them, and then releasing them back into the population. After a period of time, a second sample is taken. The proportion of marked individuals in the second sample is used to estimate the total population size.

The fundamental principle behind mark-recapture is that if a population is relatively stable, the ratio of marked to unmarked individuals in the second sample should be representative of the ratio of marked individuals to the total population size in the first sample. Several formulas exist to calculate population estimates, with the Lincoln-Petersen index being one of the simplest. This method is widely applied in ecology for studying wildlife populations, such as birds, fish, and insects, as well as in other fields like epidemiology to estimate the prevalence of diseases.

Assumptions are crucial for the validity of mark-recapture studies. These include the assumption that the marked individuals mix randomly with the unmarked population, that the marks are not lost or overlooked, that there are no births, deaths, immigration, or emigration between the marking and recapture events, and that the marking itself does not affect the survival or behavior of the individuals. Violations of these assumptions can lead to biased population estimates.